Tube Preamp

Old timers who have been around for the last 40 years or so have been fortunate enough to have lived through several audio reproduction technologies – Vinyl Records, Cassette Tapes, Laser Disks and CD-ROM’s. Most will also swear that analog, especially vinyl records, sounded the best. And when it comes to amplifiers, nothing comes close to the richness of vacuum tubes.

[MCumic10] had a long time desire to build his own HiFi turntable encased in a nice wooden housing, with the electronics embedded inside. When he chanced upon an old and battered turntable whose mechanism barely worked, he decided to plunge right in to his pet project. The result, at the end of many long months of painstaking work, is a stunning, beautiful, wooden turntable. Especially since in his own words, “I didn’t have any experience in electronics or woodworking before I started this project so it took me many long months in learning analyzing and frustration. I burned some electronic parts few times and made them from the beginning.”

The build is a mix of some off the shelf modules that he bought off eBay and other sources, and some other modules that he built himself. He’s divided the build in to several bite sized chunks to make it easy to follow. The interesting parts are the 6N3 Valve Preamplifier (the main amplifier is solid-state), the motorized Remote Volume Control Input kit, and the Nixie tube channel indicator. And of course the layered, plywood casing. By his own reckoning, this was the toughest and longest part of his build, requiring a fairly large amount of elbow grease to get it finished. He hasn’t yet measured how much it tips the scales, but it sure looks very heavy. The end result is quite nice, especially for someone who didn’t have much experience building such stuff.

It’s hard being a kid sometimes. [Young] likes his music, but his dad is an overnight trucker. With his dad sleeping during the day, [Young] has to keep the volume down to a reasonable level. He could have bought some commercial headphones, but he wanted something a bit more customized. Rather than give up on his tunes, he built a pair of headphones with an internal tube preamp amplifier. [German language link — Google translate doesn’t want to work with this one but Chrome’s translate feature works].

Two 1SH24B preamp tubes feed two LM386 amplifier chips, creating a hybrid amplifier. The 1SH24B tubes are designed to work on battery voltage, so a step up circuit wasn’t necessary. However, [Young] still needed to provide an 8 cell battery pack to run his amp. Speakers were a 3 way coaxial of [Young’s] own design. He built the headphone frame using candy tins and cups from commercial headphones. A final touch was a window so everyone can see all that vacuum state goodness. Considering that [Young] is only 16, we’re looking for some great things from him in the future.

If you don’t want to strap the tubes to your skull there are other options. But you have to admit it makes for a cool look. Starbucks here we come.